Living environment of modern society often relies on the cooperation of multiple electronic devices such as lighting control inside buildings, installation and usage of common electronic appliances (such as refrigerators and televisions), security systems (such as doorbells and closed-circuit televisions), and heat and air conditioning systems. These kinds of electronic devices usually use physical switches, such as manual switches of lights, connection to electrical sockets of refrigerators, press buttons for doorbells, valves found in water heating systems, and power switches for air conditioners. Using physical switches may be inconvenient sometimes. For example, people may need to feel around with hands to search for light switches when entering a room during night or getting up in the middle of night; people may forget to turn off lights or television when leaving a room; people may fall asleep with a television on for a whole night, wasting energy; a host may have to walk across a room to open a door when guests ring the doorbell; air conditioners need to be manually turned on and require some time to achieve a set temperature, or otherwise may need to work inefficiently for an extended period; the recording function of closed-circuit televisions in security systems generally need to be constantly turned on for a long time, which may consume large storage space. The above mentioned are only some common situations, thus it can be appreciated that although some electronic devices already incorporate some smart controlling elements (e.g., smart temperature control of a refrigerator), there is still the need for a smarter, more convenient, and more powerful environment control system.